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<script>
	console.log(1 + 1);//2
	console.log(1 + '1');//拼接能力,
	//除了加号 - * / %  没有其它功能了，就是一个计算
	//一旦有运算符，这个程序默默的先把字符串转化为number
	console.log(2*'3');//6
	console.log(6 - '3'); //3
	console.log(4 / '3');//
	console.log(2 % '3');//2
	console.log(2*'3abc');//NaN
	console.log(2 * false);//  2*?=0 false也会隐式转化结果0
	console.log(2 * true);//	 2*?=1 true也会隐式转化结果1
	console.log(2 * null); //  2*?=0 false也会隐式转化结果0
</script>